Sheet material for use in the manufacture of shoes, method of making same and shoe insole

Abstract

A sheet material suitable for use in the manufacture of shoes comprising a non-woven fiber fabric having a stiffening thermoformable binder impregnated into and extending inwardly from one surface of the fabric for a depth of more than 0.25 mm and the remaining part of the fabric being impregnated with a resilient rubbery binder and having a lower binder to fiber weight ratio than the region impregnated with the stiffening thermoformable binder. A method of making a material and a shoe insole including the material are also described.

1 . A sheet material suitable for use in the manufacture of shoes comprising a non-woven fibre fabric having a stiffening thermoformable binder impregnated into and extending inwardly from one surface of the fabric for a depth of more than 0.25 mm and the remaining part of the fabric being impregnated with a resilient rubbery binder and having a lower binder to fibre weight ratio than the region impregnated with the stiffening thermoformable binder.  
     
     
         2 . A sheet material according to  claim 1  wherein the stiffening thermoformable binder penetrates inwardly for a depth of at least 1 mm into the fabric.  
     
     
         3 . A sheet material according to  claim 1  wherein the stiffening thermoformable binder extends inwardly for a depth of from 1.5 mm to 3 mm into the fabric.  
     
     
         4 . A sheet material according to  claim 2  wherein the stiffening thermoformable binder extends inwardly for a depth of from 1.5 mm to 3 mm into the fabric  
     
     
         5 . A sheet material according to any of claims  1 - 4 , wherein the stiffening thermoformable impregnant extends inwardly for a thickness of not more than 50% of the thickness of the fabric.  
     
     
         6 . A sheet material according to  claim 1 , where the weight ratio of the thermoformable binder to fibre in the region of the fabric impregnated by the thermoformable binder is from 0.3:1 to 3:1.  
     
     
         7 . A sheet material according to  claim 1 , where the weight ration of the rubbery resilient binder to fibre is from 0.15:1 to 1.5:1.  
     
     
         8 . A sheet material according to  claim 1 , where the impregnated fabric has a thickness between 3 mm and 10 mm, the fibres have a decitex between 1.7 and 17 and a staple length between 30 and 80 mm, and the density of the impregnated fabric is between 0.01 and 0.1 g/cm 3  (10-100 kg/m 3 ).  
     
     
         9 . A sheet material according to  claim 1 , wherein the resilient rubbery binder is nitrile rubber.  
     
     
         10 . A sheet material according to  claim 1 , wherein the stiffening thermoformable binder is a thermoformable styrene-butadiene copolymer.  
     
     
         11 . A shoe insole comprising a sheet material, wherein the sheet material comprises a non-woven fibre fabric having a stiffening thermoformable binder impregnated into and extending inwardly from one surface of the fabric for a depth of more than 0.25 mm and the remaining part of the fabric being impregnated with a resilient rubbery binder and having a lower binder to fibre weight ratio than the region impregnated with the stiffening thermoformable binder.  
     
     
         12 . A method of making a sheet material comprising the following steps: 
 (i) procuring a non-woven fibre fabric    (ii) impregnating the fabric with a liquid material which when dried provides a resilient rubbery binder    (iii) drying and, if necessary, curing the liquid material to provide a resilient rubbery binder binding the fibres of the fabric together    (iv) after the rubbery binder has dried, applying a coating of a relatively viscous liquid binder composition to one surface of the fabric, this binder composition being such that when dried and, if necessary, cured it provides a stiff thermoformable binder    (v) while the coating is still viscous passing the coated fabric through a gap between a pair of nip rolls, the gap being such that the binder composition is impregnated into the fabric for a depth of more than 0.25 mm and    (vi) drying and, if necessary curing, the binder composition.    
     
     
         13 . A method according to  claim 11  in which the binder composition is impregnated into the fabric for a depth of at least 1 mm.  
     
     
         14 . A method according to  claim 11  wherein the binder composition is impregnated into the fabric for a depth of from 1.5 to 3 mm.  
     
     
         15 . A method according to any one of the claims  11  and  13  wherein the wet weight of the binder composition is 300-800 grams per square meter.  
     
     
         16 . A method according to any one of  claims 11  to  13  wherein the gap between the nip rolls is less than 25% of the uncompressed thickness of the fabric.  
     
     
         17 . A method according to any one of  claims 11  to  13  wherein the viscosity of the wet binder composition is at least 15,000 c.p.s.